Ciphering system



L. F. MOREHOUSE. CIPHERING SYSTEM. APPLICATION FILED vac-4. 1918.

Patented Ot. 26,1920.

IN V EN TOR.

LEJ/awame v BY A TTORNEY' UNHTE STATES PATENT LYllriA'NtF. MOREHOUSE, 0FMONTCLAIR, NEW JERSEY, ASSIGNOR TO AMERICAN T EL'E- PHONE AND TELEGRAPHCOMPANY, A CORPORATION OF NEW YORK.

CIPHERING SYSTEM.

Specification of Letters ma.

Patented (Oc 26., 1192611.

Application filed December a, 1918. Serial No. 265,307.

T 0 all whom it may concern Be it known that I, LYMAN F, MOREHOUSE,

residing at Montclair, in the county of Essex and State of NewJersey-have invented certain Improvements in Ciphering' Systerns, ofwhich the following is a specification. a

This invention relates to the secret communication of intelligence andfinds a particularly useful application in systems for enciphering anddeciphering messages such as set forth in the copending application ofG. S. Verman, 253,962, filed September 13, 1918, and assigned to theassignee of this application, but is applicable to any ciphering ordeciphering system where the key used is to be changed frequently.

The application above referred to discloses a secret system employingthe ordinary printing telegraph equipment using the five unit code andin which the five sending relays and the live receiving relays, areunder the joint control of a keyboard or tape transmitter and a secondtransmitter serving to encipher and decipher the message. The circuitsof the sending and re ceiving relays, instead ofbeing all grounded uponone side, may thus be connected to either battery or ground, dependingupon the positions of the contacts of this second transmitter. in such asystem it will be obvious that the impulses transmitted to the line, orto the printer, as the case may be, will not represent the character setup on the keyboard or tape transmitter but some other character,depending upon the momentary connections oftheopposite ends of the relaycircuits. The operation of the sending relays is thus dependent upon thecombined effect of the two transmitting devices. li the contacts of theenciphering and deciphering transmitter were set permanently torepresent some character such as A whose symbol is the charactertransmitted would obviously be different from the characters of themessage, butthe message could then be deciphered by an expert withlittle diiiiculty. it, however, the arrangement of the contacts in theenciphering transmitter is altered at inter vals, the deciphering ismore difiicult and becomes progressively more so as the intervals areshortened. if the arrangement of the contacts be changed with eachcharacter transmitted, the deciphering is well nigh impossible, and ifthe sequence of changes is never repeated, deciphering beof positionsfor the contacts thereof, which does not repeat, or which repeats atsuch unfrequent intervals as to be equivalent to a continuously changingseries for all prac tical purposes. To produce a tape to give such aseries of changes in a system such as shown in the above mentionedapplication would be expensive and burdensome and the use of a tapewould be inconvenient because of 1ts extreme length. The presentinvention provides a system in which a continuously changing series ofarrangements for the enciphering contacts may be produced in a simpleand convenient manner.

While the invention. is here illustrated by an embodiment particularlyfitted for use in the system above mentioned, it is, to be noted that inits broader aspects it is applicable to ciphering and decipheringsystems generally, whether or not they involve the use of mechanical orelectrical devices.

In the accompanying drawings Figure 1 :is a diagrammatic illustration ofone embodiment of the inyention and Fig. 2 indicates its application totheweceiving distributer of a printing telegraph equipment.

A represents a transmitter upon which the characters of the message tobe enciphered or deciphered are set up in succession. This may be a tapetransmitter or a keyboard transmitter such as are commonly used inprinting telegraphy. in either case there are five contacts 1, 2, 3, 4and 5 which may be made to form either the positive or negativeterminals of five control circuits. For this purpose the contacts may,as shown on the drawing be movable between positive and negativebus-bars, connected to the opposite poles of a battery 6. Two othertransmitters X and Y, which may conveniently be ordinary tapetransmitters, are used to accomplish the enciphering and deciphering ofthe characters set up at A. These transmitters, like that abovedescribed, are provided with five contacts each, indicated at 1, 2 3 4and 5* and 1 2", 3 4 and 5' respectively, which may be made to formeither positive or negative circuit terminals. The correspondinglynumbered contacts in the transmitters X an Y are united through thewindings of relays 1, 2, 3, 4 and 5, each of which is provided withafront and back contact connected to the positive and negative polesrespectively of the battery 6 or other convenient source of current. Thearmatures 11, 12, 13, 14 and 15 of these relays take the place of theoscillatlng contacts of the enciphering transmitter in a system whereonly one such transmitter is used. The magnets 1, 2, 3, 4 and 5represent the operating magnets or relays of any selectively operatedmechanism which is to deal with the enciphering or deciphering of themessage, such, for instance, as the selecting magnets for controlling aprinter or a perforator, or the selecting relays used in connection withthe distributer in transmitting impulses over the line, all of which areinstruments now in common use in printing telegraph sets. These relayshave their windings connected between the contacts 1, 2, 3,4 and f thetransmitter A and the armatures 11, 12, 13, 14 and 15 of the controllingrelays.

The contacts of the transmitter A are operated either by hand or by atape to represent the characters of the original or the encipheredmessage (depending upon whether the message is to be enciphered ordeciphered.) Each of the transmitters X and Y is provided with aseparate perforated tape or equivalent record'having a series ofcharacters represented thereon preferably selected atrandom. One ofthese tapes has a greater number of characters than the other, adifference of one character being convenient and sufiicient for thepurpose in hand. These tapes or records are preferably in the form ofclosed bands so that each may travel continuously through itstransmitter the operation beginning at any selected point thereon. Withthese bands in place and operating it will be obvious at once that thecombination of relays of the set 1, 2, 3, 4 and 5 to be operated at anygiven time depends upon the two characters which happen at the moment tobe in the transmitters X and Y, since none of these relays will operate,if the contacts to which its opposite terminals are connected bothhappen to be upon positive or both upon negative bus-bars, but willoperate if either terminal i upon a positive and the other upon anegative bus-bar. "When one tape has completed one revolution, the othertape, being of a different length, will have overrun or have failed tocomplete a revolution and in the following round of the tapes thecombination characters set up in the relays 1, 2, 3, 4 and 5 willaccordingly be a different series from that set up during the firstround; 1f, for e -ple, one or these tapes be provided w a thousandcharacters and the other ters {which are i the two tap s can pass 999times through the two transmitters before the original series ofcombination will be repeated.

Therefore, the two tapes thus operating provide 999,000 charactercombinations in the relays 1, 2, 3, 4 and 5 before they begin to repeatthe series. Such a number as this Will serve for a considerable periodof message transmission and if it is desired to avoid a repetition evenas often as this, further key tapes providing other series of likelengths can readily be provided.

The arrangement of contacts shown on the drawing illustrates the mannerin which the enciphering, according to this system, will proceed. Thetransmitter A has its first, second and fourth contacts shifted to thepositive bus-bars, thus representing the symbol for the letter J, or Thetransmitter X has its fourth and fifth contacts shifted, thusrepresenting the symbol for the letter O, or The transmitter Y has itssecond and fourth contacts shifted, thus representing the symbol for theletter R, or In the set of relays 1, 2, 3, 4, 5, armature 11 will beunaffected since both terminals of the relay winding are connected tothe negative pole of the battery. Armature 12 will be shifted since thewinding is connected to the nega tive pole at X and to the positive poleat Y. Armature 13 will be unaffected since the relay winding isconnected to the negative pole at both ends. Armature 14 will beunaffected since the relay winding is connected Arma windpositive po eat X to the positive pole at both ends.

ture 15 will be shifted since the rela ing is connected to the and thenegative pole at Y. In this set of relays, therefore, we have the secondand fifth contacts shifted, representing the symbol for the letter L, orThe magnet 1 of the device to be selectively operated will receivecurrent, since its winding is connected to the positive pole at A andthe negative pole at 1. The magnet 2 will be unaffected since it isconnected to the positive pole at both ends. Magnet 3 will be unaffectedsince it is connected to the negative pole at both ends. Magnet 4 willbe operated since its winding is connected to the positive pole at A andthe negative pole at 4. The magnet 5 will be operated since it isconnected to the negative pole at A and the positive pole at 5. That isto say, the first, fourth and fifth armatures of the magnets to beselectively controlled are shifted, thus representing the symbol for thecharacter Supposing therefore, the tape in the transmitter A torepresent the unciphered message the letter of this message will berepresented i ciphered form Dec 'aner e having the transmitter A. At thesame point in the message the transmitter A would then have its contactset to represent the letter B and by tracing the resulting circuits itwill be found that the controlling magnets "1, 2, 3 4 5 will thenrepresent the letter J.

If it is desired to use the double tape system above described fordeciphering messages as they are received over the line, the windings ofthe magnet 1 2 3 4 and 5 are connected on one side to the five contactsof the receiving distributer as shown in Fig. 2 instead of to the fivecontacts of the transmitter A and the line relays over which theimpulses are received will operate an armature which is connected to thecontinuous ring 16 of the distrib uter and the front and back contactsof the relay armature will be connected to the opposite poles of thebattery 6. The magnets 1 2 3, 4

and 5 will then receive the same impulses as if their terminals wereconnected to the transmitter A, except that the impulses will besuccessive instead of simultaneous. Existing apparatus is arranged touse them in either way.

By the use of two key tapes as herein described, it is obviouslypossible to transmit messages for an indefinite period without repeatingthe series of characters used to encipher and decipher the message, anddo this without the inconvenience of using excessively long tapes or anextremelylarge number of tapes as would otherwise be necessary.Obviously the combining of the effects of key tape in accordance withthis invention is not limited to the use-of a sin le pair. Any desirednumber may be used Ty combining them-so asultimately to have theireffects united in a single set of contacts such asthose indicated hereinat 11, 12, 13, 14, 15.

It will be clear that the invention is not limited to the use ofperforated tapes, or any other particular form of-record for the seriesof ciphering characters nor to any particular electrical or mechanicalmeans for combining the characters from the several series to producethe running. key by which the -enciphering and deciphering areaccomplished. It is not important in the use of the invention that theeffect of combining the two or more characters from different seriesshould be actually manifested in a discernible form. In the embodimentof theinvention above described, characters or symbols representing therunning key are not recorded, though they could be discerned from theposition of the armatures of relays 11 to 15 if these are so located asto be visible. sary since the same result is obtained if the successiveeffects of the combination of two symbols from different series arecombined by predetermined rule in any convenient But even this is notnecesway with symbols representing the successive message characters. Topractice the invention it is only necessary that there shall beplurality of series of ciphering characters, differing in length,so-that they may be used repeatedly for combining with another serieswithout producing a cyclic repetition of the same character or sequenceof characters in the resulting series, and that each character beassigned a definite form, position, value or other characteristic (theelectrical symbols, such as for A, in the embodiment above described)such -that those for characters of different series may be combined, inaccordance with some predetermined rule, to produce definite effects,indications or symbols, which in turn are similarly combinable withcharacteristics assigned to the characters of the message.

Even in the specific embodiment of the invention herein described, itwill be clear that it is not limited to the particular arrangement ofcircuits and contact devices shown and described, as variousmodifications will readily suggest themselves with out departing fromthe spirit of the invention.

What is claimed is: l

1. The method of enciphering or deciphering messages which consists informing a plurality of series of ciphering characters with the number ofcharacters different in each series, selecting, characters from eachseries in a fixed order to form a continuous sequence by retraversingthe series as it is exhausted, and altering the message characters inaccordance with a predetermined rule whose effect upon successivemessage characters is dependent upon the concurrent use of characters soselected from different cipher series.

2. The method of enciphering or deciphering messages which consists informing a plurality of series of ciphering characters,

assigning to each character a characteristic combinable, in accordancewith a predetermined rule, with the characteristic of any character inanother series to produce a definite effect, and determining thecharacters of the enciphered or deciphered mes sage by combiningrepresentations of the successive message characters to the sucandcombining the characteristics of the successive message characters withsuccessive effects produced by combining the characteristics ofcharacters in the different series to determine the characters of theenciphered or deciphered message.

4. The method of enciphering or deciphering messages which consists incombining the successive code symbols of a plurality of predeterminedseries of unequal length, repeatedly used to produce a cipher key havinga long series of symbols Without cyclic repetition of the same symbol orsequence of symbols, and combining the successive symbols of the cipherkey. so produced with the code symbols of the successive messagecharacters to indicate the successive characters of the enciphered ordeciphered message.

5. The method of producing a cipher key, free from cyclic repetition ofthe same character or sequence of characters, which consists in forminga plurality of series of ciphering characters with the number of"characters different in different series, selecting characters from eachseries to form a continuous sequence by retraversing the series as it isexhausted, and combining the successively selected characters fromdifferent series.

6. The method of producing a cipher key free from cyclic repetition ofthe same char: acter or sequence of characters, which consists informing a plurality of series of ciphering characters with the number ofcharacters different in each series, selecting characters from eachseries to form a continuous sequence by retraversing the series as it isexhausted, and combining the successively selected characters fromdifferent series in accordance with a predetermined rule.

7. The method of producing a cipher key free from cyclic repetition ofthe same character or sequence of characters, which'consists in forminga plurality of series of ciphering characters with the number ofcharacters in at least one series different from that in the others,assigning to each character a characteristic combinable in accordancewith a predetermined rule with the characteristics of characters in theother series, selecting characters from each series to form from each acontinuous sequence by retraversing the series as exl'iausted, andcombining the successively selected charac- .ers' from different seriesin accordance with a predetermined rule.

8. A ciphering and deciphering device comprising a plurality of keyrecords each composed of a series of ciphering characters with thenumber of characters different in each series, ,and each characterhaving a characteristic combinable in accordance With a predetermined ewith the characteristics of characters in another series,

and means responsive to the combined effect of successively selectingcharacters from the different series for indicating the character of theenciphered or deciphered message corresponding to a given messagecharacter.

9. In a ciphering and deciphering device a plurality of key records,each bearing a number of code symbols arranged in an endless clos'edseries, the number of symbols in the two series being different indifferent series, groups of controlling members, one group associatedwith each key record, and adapted to represent successively the sym bolsthereon, another group of controlling members adapted to representsuccessively the character symbols of the message to be enciphered ordeciphered, and means under the joint control of said groups of membersfor indicating characters of the enciphered or deciphered message.

10. In a ciphering and deciphering device, a plurality of records, eachbearing a number of code symbols arranged in an endless closed series,the number of symbols being different in different series, groups ofcontrolling members, one group associated with each key record andadapted to represent successively the symbols thereon, mechanismresponding to the joint control of said groups of members to repre sentthe combined effect of the symbolsmomentarily controlling the groups,another group of controlling members adapted to represent successivelythe character symbo'ls of the message to be enciphered or deciphered,and means under the joint control of said mechanism and said other groupof members for indicating the characters of the enciphered or decipheredmessage.

11. In a ciphering and deciphering device, a plurality of key records,each bearing a number of code symbols arranged in an endless closedseries, the number of symbols being different in each key, groups ofcontrolling members, one group associated with each key record andadapted to represent successively the symbols thereon, a group ofdevices adapted to represent successively the character symbols of themessage to be enciphered or deciphered, and means under the jointcontrol of said groups of controlling members and said devices forindicating the characters of the enciphered or deciphered message.

12. A ciphering and deciphering device comprising a plurality of keytapes, each in form of a closed loop bearing a continuous series ofcharacter symbols thereon whose number is different on at least two ofthe tapes, mechanism under the control of said tapes for combining theeffects of single symbols from each of the several tapes, and means forsimultaneously moving the tapes forwa to bring successive symbols oneach taps into position to affect said mechanism,

V ering messages comprising twocontrolluig reac es whereby a series ofkey symbols may be produced which is long, compared with either of thetape series and is free from cyclic repetitions of the same symbols orsequence of symbols.

13. A ciphering and deciphering device comprising two key tapes, eachinform of a closed loop bearing a continuous series of character symbolsthereon, whose number is different on the two tapes, mechanism under thecontrol of said tapes for combining the effects of two symbols, one fromeach tape,

and means for simultaneously moving the tapes forward to bringsuccessive symbols on each tape into position to afiect said mechanism,whereby a series of key symbols may be produced which is long, comparedwith eitherof the tape series and is free from cyclic repetitions of thesame symbol or sequence of symbols.

14.'In a device for enciphering and deciphering messages, mechanism forrecording the enciphered or deciphered message, means for indicatingsuccessively the code symbols of the message to be enciphered ordeciphered, a' set of devices capable of rep resenting a long series ofcode symbols corresponding to the key used for the encipher;

ing and deciphering, and means for controlling said devices comprising aplurality of mechanisms and means for operating each mechanism to reresent a shorter series of symbols, the vnum er of symbols beingdifierent in at least two of eachiofthe shqrter series and the seriesbeing retrav-' ersed as it is exhausted. p

15. A device for enciphering and deciphdevices, a key tape for operatingeach device, each key ta e bearing a series of code symbols, the numberof symbols on one tape differing from that on the other and mechanismunder the joint control of said devices for indicating the enciphered ordeciphered message characters.

16. A device for enciphering or decipher ing messages comprising two keytapes in the form of closed loops bearing character mbols thereon thenumber on one tapeeach key tape for representing the successivdcharacters indicated thereon, a group of rellays-whose windings arecontrolled respectively by the corresponding contacts in said sets, agroup of contacts for successively re'presentingthe characters of'themessage,

and mechanism responsive to the condition of said relays and said lastmentioned set of' contacts for indicating-the characters of theenciphered or deciphered message,

In testimony whereof I have'si 'ed my name to this specification thisthirtieth day of November, 1918.

LYMAN F. MOREHOUSE'.

